About 80 kinds of metals are dissolved at low concentrations of ions in seawater accounting for approximately 70% of the earth, including uranium (4.1 billion tons), 10 strategic rare metals in Korea, including manganese (2.7 billion tons), molybdenum (14.0 billion tons), cobalt (140 million tons), tungsten (100-million 4-thousand tons), titanium (1.4 billion tons), lithium (200 billion tons), magnesium (1,840 trillion tons), indium (27.2 billion tons), rare earth metals (4.2 billion tons) and chrome (68 million tons), and vanadium (2.7 billion tons), germanium (80 million tons), bismuth (20 million tons), and the like. In particular, magnesium (1,840 trillion tons), lithium (200 billion tons), molybdenum (14.0 billion tons), and uranium (4.1 billion tons) are highly likely to be commercialized.
Accordingly, much effort to selectively separate and recover precious metal ions such as lithium and uranium in low concentration from seawater and recycle them as resources has been made.
However, in the case of recovering precious metals dissolved in seawater or the like, the precious metals are not sufficiently concentrated due to too low concentrations thereof, which may cause excessive consumption of power, and thus fail to realize a commercially useful process.